Sen. Barbara Boxer, Attorney General Jerry Brown, House Speaker Nancy Pelosi and former San Francisco Mayor Willie Brown are four California Democrats with national profiles who have rarely been shy about speaking their minds or taking unpopular stands.

None has ever shown an aversion to a reporter's microphone, for that matter. Except when it comes to endorsing a candidate for president in the Democratic primary. If you're the kind of voter who wants to know where your favorite politician is leaning before you cast your ballot, don't look to these four. They're not saying.

They're not even swayed to provide an example after seeing a Field Poll released this month which showed that 20 percent of Democratic primary voters are undecided before the Feb. 5 California primary.

Some conflicts are straightforward. Willie Brown is working as a political analyst on local and national television. Endorsing a candidate would damage his TV pundit cred.

"I've never been high on endorsements," Brown said. "When you get one, all it does is keep the other guy from getting one. Really, what did getting John Kerry's endorsement do to help Barack Obama?"

Brown said the Obama campaign could have best used Kerry to answer former President Bill Clinton's recent jabs at the Obama campaign. "Don't let the candidate answer those," Brown quipped. "Put the windsurfer out there."

Pelosi is head of the Democratic National Convention. A little over a year ago, she made much of shattering the glass ceiling in Congress when she became the first woman to become House speaker. But that doesn't mean she's favoring Sen. Hillary Rodham Clinton, who is aiming to bust the glass ceiling at the White House. Or Obama, who would be the nation's first African American president. Or former Sen. John Edwards.

In Pelosi's current party role, favoring one candidate would be the political equivalent of favoring one of her children over another.

"Let the Democratic process continue," Pelosi said Friday after offering the Democratic Party's "prebuttal" to today's State of the Union address by the president. "Whoever the nominee is, we will all rally behind, lift up, be very proud of and move on to victory in November. So I'm very proud of each and every one of our candidates, Senator Edwards, too, and look forward to supporting one of them very soon."

Jerry Brown is no stranger to staking new political turf. Thirty years ago, as California's governor, he was ahead of public opinion on gay rights and environmental protection. He appointed Rose Bird as the first woman to serve in the state Supreme Court, though her anti-death penalty position prompted her recall by California voters. As mayor of Oakland, he bucked many in the city's entrenched political interests by backing downtown housing development.

But endorse a Democrat in the presidential primary race? "Attorney General Brown is not prepared to weigh in on that and doesn't have anything more to say," said Brown's spokesman Gareth Lacy.

You'd think he might back Clinton, whose state campaign manager is Ace Smith - the same man who ran Brown's successful attorney general run last year.

Then again, there may be a little bad blood going back to 1992, when Jerry Brown ran for president in the Democratic primary against Bill Clinton. At a debate in Chicago, Brown cited a Washington Post story that the law firm that Hillary Clinton worked for did business for the state of Arkansas. Brown accused Clinton of "funneling money to his wife's law firm for state business."

"You ought to be ashamed of yourself for jumping on my wife," Bill Clinton responded at the televised debate.

Turning toward Brown, Clinton said, "He comes up here with his family wealth and his $1,500 suit and makes a lying accusation about my wife," Bill Clinton said. "I'm saying I never funneled money to my wife's law firm. Ever."

Boxer has been silent so far because she considers Obama and Clinton to be "friends and allies, and as long as both are in the race she will remain neutral," said spokeswoman Natalie Ravitz.

But Democratic Sens. Dick Durbin, D-Ill., and Chuck Schumer, D-N.Y., are roommates in Washington and they have picked sides. Durbin is for Obama, Schumer for Clinton. California Sen. Dianne Feinstein, who with Boxer was first elected to the Senate in 1992, supports Clinton.

"Sen. Boxer has great respect for Sen. Feinstein and great respect for her opinion, but they are two independent thinkers - they are not joined at the hip," Ravitz said.

Indeed, prominent Bay Area Democrats are splitting from their ideological and colleagues.

Rep. Barbara Lee, D-Oakland, has campaigned in South Carolina for Obama, while her political mentor, Oakland Mayor Ron Dellums, is an urban affairs adviser for Clinton. Rep. George Miller, D-Martinez, is a high-ranking House member who supports Obama. His East Bay congressional neighbor, Rep. Ellen Tauscher, D-Walnut Creek, supports Clinton. Rep. Lynn Woolsey, D-Petaluma, co-chairs the Congressional Progressive Caucus with Lee, but backs Clinton. San Francisco Mayor Gavin Newsom endorsed Clinton, while District Attorney Kamala Harris worked in Iowa for Obama and is one of the campaign's top California organizers.

Boxer can't afford to tick off anybody by taking sides. Not when she is trying to raise $20 million for her Senate re-election campaign.

Indeed, last February she announced that she'd run for re-election in 2010 - at a fundraiser hosted by Obama. Yet her ties to the Clintons are familial. Her daughter Nicole married Hillary Clinton's brother, Tony Rodham. They divorced in 2000 and have one child.

Or is Boxer's reticence rooted in the political? In 2002, Boxer voted against giving President Bush the authority to use force in Iraq. Clinton and then-Sen. Edwards voted for it. Boxer has characterized her decision as "the best vote of my life."

Boxer is also a favorite among the "netroots" - the community of liberal online activists who raise buzz and cash for candidates. And many in the netroots community do not like Clinton for her 2002 vote.

"In the progressive community, Barbara is a champion," said Sam Rodriguez, a former political director of the California Democratic Party who is now a political strategist. "On the war, on the environment, on women's issues, she has been steadfast against the Bush administration."

Kennedy to endorse Obama

An official close to the senator said the announcement will be made today in Washington during an Obama campaign rally at American University. Obama will be joined by Kennedy and his niece, Caroline Kennedy, who endorsed Obama in an editorial Sunday in the New York Times.

Caroline Kennedy said Obama could inspire Americans in the same way her father, President John F. Kennedy, did.

"I have never had a president who inspired me the way people tell me that my father inspired them," she wrote. "But for the first time, I believe I have found the man who could be that president - not just for me, but for a new generation of Americans."

Ted Kennedy's endorsement was highly sought after by all the Democratic candidates. Besides his status as a liberal icon and member of the Kennedy dynasty, Kennedy boasts a broad national fundraising and political network.